Muscle cells possess a number of unique functional characteristics which set them apart from other cell types in higher organisms - most notably those related to excitability, the coupling of an electrical signal into muscle contraction and the contractile process itself. The long term goals of the proposed research are to understand these cellular processes at the level of the molecular mechanisms which underlie muscle cell function. The immediate aims of the proposed work will be to begin to isolate and to characterize genes which we have putatively identified to be expressed specifically in muscle cells of adult organisms and not in other cell types. It is postulated that these genes may encode proteins that are involved in the unique processes of the muscle cell. This work will entail the use of a recently devised molecular scheme involving the fruitfly Drosophila, which allows one to identify easily the spatial and temporal expression pattern of genes which have been mutagenized or are close to the site of a mutation generated by the insertion of genetically engineered transposable p-elements into the genome. Once identified, the muscle-specific genes will be subjected to further molecular analyses which include cytogenetic mapping of the physical location of the genes on polytene chromosomes and the isolation, cloning and characterization of genes of interest. Ultimately this approach may aid in understanding the structure, function and role of proteins involved in muscle cell function. Funds are requested to support one undergraduate and one graduate student. The undergraduate student will learn basic laboratory skills and specific skills related to his/her project under the direction of the P.I. and will be supervised on a daily basis by a postdoctoral fellow or advanced graduate students. By the second year, the undergraduate will be encouraged to work independently on a portion of the proposed studies. The graduate student will be supervised by the P.I. and will learn to become an independent scientist. All students will attend weekly lab meetings and seminars and will be expected to communicate the results of their studies at regional and appropriate national meetings.